Question

Mrs. Conley asks her class what kind of party they want to have to celebrate their excellent behavior. Out of all the students in the class, 5 want an ice cream party, 7 want a movie party, 10 want a costume party, and the rest are undecided.

If 20%, percent want an ice cream party, how many students are in the class?

Answer 1

I think that the answer would be 100. If I'm wrong, whoops! I'm not perfect, in fact nobody is.

Answer 2

Let's write an expression for the number of students in the class:

5+7+10+x

Of this total number of students, 5 want an ice cream party. This constitutes 20% of the class, or the decimal fraction 0.20.

Thus, 5
--------------- = 0.2 or 1/5
5+7+10+x

Then 5 1
---------- = ----
22+x 5

Solving for x: 25 = 22 + x; x=3

Then the total number of students in the class is 22+x = 22+3 + 25.

Check: is 5
----- equal to 0.20? YES
25